An analysis of the migratory behavior of avian cephalic neural crest cells☆

[摘要] Theneuralcrestcellsmigratefromtheiroriginintomanyregionsofthevertebrateembryo.Uponreachingtheirterminaldestinations,membersofthispopulationundergocytodifferentiationintoawiderangeofdiversecelltypes.Tofollowtheearlymigratorybehaviorofaviancephalicneuralcrestcells,neuralfoldtissuewastransplantedorthotopicallyfroma3H-thymidine-labeleddonorintoanunlabeledhost.Thehostsweresacrificedatsubsequentstagesandthepositionsofalllabeledneuralcrest-derivedcellsascertainedradioautographically.Crestcellsemigratingfromeachofthreedifferentpreoticregionsofthebraindisplayeduniquepatternsofmigration,whicharedescribedindetail.Havingestablishedthesenormalpatternsofneuralcrestcellmigration,thefollowingquestionwasposed:Aretheuniquemigratorypatternsofthedevelopingneuralcrestcellpopulationdeterminedwithintheindividualcellspriortotheirexodus,oraretheyimposeduponthecrestcellsbytheenvironmentthroughwhichthecellsmove?Toresolvethisproblemneuralfoldswereremovedfromoneofthethreecranialregionsdescribedaboveandreplacedwithasegmentof3H-thymidine-labeledneuralfoldfromeitheradifferentcephalicregionorthebrachialspinalcordlevel.Innearlyeverycasetheheterotopicallytransplantedcellsmimickedthenormalpatternsofmigration,andtheembryoswereindistinguishablefromthosewhichhadreceivedorthotopictransplants.Thisprovesthattheprecisepatternsofmigrationofchickneuralcrestcellsarenotirreversiblydeterminedwithinthecellspriortotheiremigration.Rather,theircomplexyethighlyorganizedmigratorybehaviorislargelydirectedbyenvironmentalinfluences.

[学科分类] 生物科学（综合）